It is impossible to develop a bond without developing leadership. Horses are herd animals, and in the herd they follow their leader without questioning as they trust that the leader knows what is best for them. This is what a bond is -TRUST. Your horse will never truly trust you unless you are his unequivocal leader.
In the herd, the leder can move the other horses feet and decide where and how fast the others go. We humans show our lederhsip by doing just that -especially when yielding the horse from the ground. So when he is scared or bossy, start yelding him. It will take his mind of it, and he will realise that he is safe because you are the leader.
You become the the leader by being fair and assertive if he quiestions your leadership -ie moves into your space, acts aggressively etc, or even shies (because if he shies he is thinking for himself, rather than trusting your leadership). Meet force and agression with equal force, but be assertive not aggressive, and stay calm and unemotional. I mean that if he walks into your circle, just casually push him out (as someone else said, suggest...ask..tell..promise). When the issue is minor then suggestion is usually enough. But if he is at the promise level ie rears and tries to strike you, then you better go staight to the promise and win by any means ie get him to yield from you. In this situation you would go from promise down to suggest until he is moving as fast as you want, in the direction you want and with no attitude. When the horse thinks for himself (ie is afraid of something) ignore his antics, ride/lead (if you were already on the ground, never dismount because that would be rewarding him for questioning you!) him past it as if its not there. You are the leader and you know best. If you go "oh no pretty pony its ok" and let him sniff it etc then you are showing him that you yourself are unsure whether it is safe and want him to to be the leader and check for you. This would make him mistrust your leadership even more, and make the problem even worse.
Sorry for the long post